I've got a '92 525 that has a leaking radiator. It appears to be leaking from the lower fin area. It seems rather soon to need to replace a radiator. Has anyone else had to do so? The car appears to have been serviced by a local dealer (I've owned the car for about 1 year)and the coolant looked ok when I purchased the car. After I bought it, I replaced the coolant with Prestone Extended Life and a few months later had to replace the water pump. Again I replaced the coolant with Prestone Extended Life. Does my choice of coolant have anything to do with the radiator failure?